<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>04_JS流程控制</title>
</head>
<body>
<script>
    console.log('1');
    console.log('2');
    console.log('3');

    let uname=' ';
    if(!uname){
        alert('请先登录')
    }else{
        alert('欢迎您:'+unam)
    }

    let gender=100;
    switch (gender){
        case 1:
            console.log('男');
            break;
        case 0:
            console.log('女');
            break;
        default:
            console.log('未知')
    }

    let names=['张三','李四','王五'];
    for (var i=0;i<names.length;i++){
        console.log(names[i]);
    }
    console.log('循环结束');
    console.log('i的值是:'+i);

    for (let n of names){
        console.log(n);
    }
</script>
</body>
</html>